WASHINGTON (CNNMoney.com) -- As lawmakers began the final push Thursday on a comprehensive Wall Street reform bill, lobbyists also made their final push -- in congressional hallways, on BlackBerrys and cell phones, and at restaurants and bars near Capitol Hill.
On Thursday, some 40 lawmakers gathered in a House committee room to give speeches and kick off a marathon, two-to-three week session of deal-making on key differences buried in the bills.
Wall Street reform bills, passed by the Senate in May and the House last December, aim to curb risk taking, protect consumers and prevent financial firms from getting too big to fail. But the chambers take different roads toward achieving those goals.
Next Tuesday, lawmakers will start hashing out specific policy differences in meetings that are open to the public and being broadcast on C-SPAN and on the House Financial Services Committee Website.
"This is going to be a very open process," said Rep. Barney Frank, D-Mass., who was elected to run the joint committee encompassing negotiators. "Nothing will be put into this final bill that is not advanced, openly debated, subject to amendment by the conference process and voted on."
Yet, the conversations that go on outside the committee room spotlights are where much of the actual wrangling and arm-twisting goes on, lobbyists and congressional experts say.
Sen. Richard Shelby, R-Ala., complained Thursday that Republicans have already been shut out of some decisions made behind closed doors, such as the shaping of first raw draft to be considered. That draft mostly reflects the Senate bill with some "House additions," according to Sen. Christopher Dodd, D-Conn., who runs the Senate Banking panel.
"I believe if we continue to proceed in this matter, however, any further assertions of openness and transparency will be a fiction, and meetings like this one will only serve as political theater," said Shelby, the ranking Republican on the Senate Banking Committee.
Here are examples of the kind of lobbying that happens outside the committee room:
"The lobbying community is not done with its work. And they are very, very focused on the conference process, and we'll be fighting any attempt to weaken the bills," said Assistant Treasury Secretary Michael Barr in a briefing with reporters two weeks ago. "There's still plenty of fight left in the process."
Since January 2009, financial service firms have spent $591 million lobbying Congress, which includes money spent on the health care reform bill as well as the Wall Street reform bills, according to the Center for Responsive Politics, a watchdog group.
Nearly every major Wall Street bank has shelled out money for lobbying, including Goldman Sachs, which has spent $3.9 million, and Bank of America, which spent $4.6 million. Smaller banks have also lobbied through banking groups. The American Bankers Association has spent $11.3 million since January 2009 and the Independent Community Bankers Association has spent $5.8 million.
Many of the lobbyists have connections to those they're lobbying. More than 1,400 of the financial service sector lobbyists working on Wall Street reform worked for lawmakers and federal agencies they're now lobbying, according to a joint analysis of federal disclosure records and other data released by the watchdog groups Public Citizen and the Center for Responsive Politics.
Another way that industries can flex their muscle is by making campaign contributions to lawmakers. Summer is the high season for fundraising, especially in an congressional election year.
Since 1989, financial, real estate and insurance firms have contributed more than $112 million to the Democrats and Republicans named to the conference committee, according to the Center for Responsive Politics.
Sen. Charles Schumer, D-N.Y., tops the list with $17.5 million, followed by Dodd at $15.1 million and Shelby at more than $7.5 million, the center reports.
"Campaign contributions may not prove to be an ultimate, deciding factor in how these lawmakers operate. But money buys access," said Dave Levinthal, spokesman for the Center for Responsive Politics. "It's awfully difficult as a member of Congress to say 'No' to a longtime Wall Street campaign contributor who wants to bend your ear or twist your arm at this critical juncture."
And more money will roll in while negotiations are going on. Lawmakers on the conference committee with scheduled fundraisers include Rep. Carolyn Maloney, D-N.Y., Rep. Spencer Bachus, R-Ala., Rep. Frank Lucas, R-Ohio, and Rep. Jeb Hensarling, R-Texas, according to a database of invitations compiled by the watchdog group Sunlight Foundation.
Frank was also scheduled to have one Thursday morning, but it was postponed.